The present invention relates to a clutch arrangement for a motor vehicle drive train, wherein the clutch arrangement has a first and a second clutch which are embodied as normally open clutches, wherein the first clutch can be activated from an open position into a closed position by means of a first actuator arrangement, and wherein the second clutch can be activated from an open position into a closed position by means of a second actuator arrangement, and wherein the clutch arrangement has a locking device for locking a clutch in the closed position.
A clutch arrangement of this type is known from document DE 199 17 724 A1. This document discloses a separate locking device for each of the two clutches, said locking devices being activated simultaneously in order to bring about a parking brake function so as to block the transmission in the stationary state.
In addition, document DE 10 2007 023 955 A1 discloses a friction clutch which can be secured by means of a mechanical securing device in a predefined position from which the clutch can be quickly activated.
Clutch arrangements of the type specified at the beginning can be used, for example, as clutch arrangements in double clutch transmissions, wherein the clutch arrangement is arranged between a drive engine and a step-by-step variable speed transmission having a plurality of gearspeeds, and wherein the step-by-step variable speed transmission has two component transmissions here. Each component transmission is assigned different gearspeeds, wherein as a rule one of the component transmissions is assigned the even-numbered gearspeed stages and the other component transmission is as a rule assigned the odd-numbered gearspeed changes.
In addition, a clutch arrangement of the specified type can also be used for a drive train in which the drive engine is formed by an electric motor and in which the transmission has only two gearspeed stages. In this context, the clutch arrangement serves either to shift the one gearspeed stage or the other gearspeed stage into the power flux to a differential of a driven axle.
The clutches are preferably embodied as friction clutches, in particular as wet-running multi-disk clutches. The friction clutches can, however, also be embodied as dry friction clutches.
In the two above-mentioned application cases, the two friction clutches can be activated in an overlapping fashion in order to be able to carry out a gearspeed change under load.
Friction clutches of this type are as a rule activated in an automated fashion by means of actuator arrangements. In this context, stringent safety requirements have to be met since simultaneous closing of both clutches can bring about blocking of the transmission and therefore blocking of a driven wheel.
Friction clutches of this type can either be embodied as normally closed or as normally open friction clutches. Normally closed friction clutches are generally pressed into the closed position, for example by means of a mechanical spring arrangement, and opened by means of the actuator arrangement. Normally open friction clutches are prestressed into an open position, for example by means of a mechanical spring arrangement, and are moved into the closed position by means of an actuator arrangement.
Normally open friction clutches are less problematic in technical safety terms for the reasons mentioned above. However, it is disadvantageous that the friction clutch which is respectively conducting power has to be kept continuously closed during operation of the clutch arrangement by means of the actuator arrangement (as a rule counter to a mechanical spring force), which leads to increased energy consumption.